Effective use of methane that has been produced by methanation by allowing carbon dioxide to react with hydrogen has been examined Patent Documents 1 to 3 have proposed, as a catalyst used for such a methanation reaction of carbon dioxide, for example, an amorphous alloy catalyst ribbon produced by melting an alloy of iron group metals such as Ni and Co, and valve metal such as Zr, Ti, Nb, and Ta, and thereafter solidifying the melt by melt-quenching.
Such an amorphous alloy catalyst allows efficient conversion of carbon dioxide to methane, and has a high conversion ratio from carbon dioxide to methane. However, because it is produced by melt-quenching, it is not suitable for mass production, and because it is a ribbon type, disadvantages are that applicable reactors (reaction system) are limited.
Thus, a powder methanation reaction catalyst that is highly mass productive, and is widely applicable to various reactors (reaction systems) is desired.
Patent Document 4 has proposed, for such a powder methanation reaction catalyst, for example, a carbon dioxide methanation catalyst prepared by immersing a tetragonal zirconia support in an aqueous solution of salt of Ni and/or Co, and then drying and calcining the mixture, and then, reducing the calcined product: the tetragonal zirconia support including one or two stabilizing element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Eu, Mg, and Ca.
Furthermore, improvement in carbon dioxide conversion ratio of the powder methanation reaction catalyst has been examined.
For example, Patent Document 5 has proposed a methanation reaction catalyst prepared by mixing zirconia hydrosol, an aqueous solution of a salt of a stabilizing element, and an aqueous solution of a salt of an iron group element, and then drying and calcining the mixture, and then, reducing the calcined product. In the methanation reaction catalyst, a portion of an iron group element is incorporated into the tetragonal zirconia support along with a stabilizing element, and the metal state iron group element is supported on the tetragonal zirconia support.